pxfm/exponents/
expf.rs

1/*
2 * // Copyright (c) Radzivon Bartoshyk 4/2025. All rights reserved.
3 * //
4 * // Redistribution and use in source and binary forms, with or without modification,
5 * // are permitted provided that the following conditions are met:
6 * //
7 * // 1.  Redistributions of source code must retain the above copyright notice, this
8 * // list of conditions and the following disclaimer.
9 * //
10 * // 2.  Redistributions in binary form must reproduce the above copyright notice,
11 * // this list of conditions and the following disclaimer in the documentation
12 * // and/or other materials provided with the distribution.
13 * //
14 * // 3.  Neither the name of the copyright holder nor the names of its
15 * // contributors may be used to endorse or promote products derived from
16 * // this software without specific prior written permission.
17 * //
18 * // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19 * // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
21 * // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
22 * // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
24 * // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
25 * // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
26 * // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 * // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29use crate::common::{f_fmla, f_fmlaf, fmlaf, pow2if, rintfk};
30use crate::polyeval::f_polyeval5;
31use crate::round::RoundFinite;
32
33const L2U_F: f32 = 0.693_145_751_953_125;
34const L2L_F: f32 = 1.428_606_765_330_187_045_e-6;
35const R_LN2_F: f32 = std::f32::consts::LOG2_E;
36
37/// Exp for given value for const context.
38/// This is simplified version just to make a good approximation on const context.
39#[inline]
40pub const fn expf(d: f32) -> f32 {
41    const EXP_POLY_1_S: f32 = 2f32;
42    const EXP_POLY_2_S: f32 = 0.16666707f32;
43    const EXP_POLY_3_S: f32 = -0.002775669f32;
44    let qf = rintfk(d * R_LN2_F);
45    let q = qf as i32;
46    let r = fmlaf(qf, -L2U_F, d);
47    let r = fmlaf(qf, -L2L_F, r);
48
49    let f = r * r;
50    // Poly for u = r*(exp(r)+1)/(exp(r)-1)
51    let mut u = EXP_POLY_3_S;
52    u = fmlaf(u, f, EXP_POLY_2_S);
53    u = fmlaf(u, f, EXP_POLY_1_S);
54    let u = 1f32 + 2f32 * r / (u - r);
55    let i2 = pow2if(q);
56    u * i2
57    // if d < -87f32 {
58    //     r = 0f32;
59    // }
60    // if d > 88f32 {
61    //     r = f32::INFINITY;
62    // }
63}
64
65// Lookup table for exp(m) with m = -104, ..., 102.
66//   -104 = floor(log(single precision's min denormal))
67//    103 = ceil(log(single precision's max bessel K(n) that will be used))
68// Table is generated with SageMath as follows:
69// for r in range(-104, 103):
70//     print(double_to_hex(RealField(180)(r).exp()) + ",")
71pub(crate) static EXP_M1: [u64; 207] = [
72    0x368f1e6b68529e33,
73    0x36a525be4e4e601d,
74    0x36bcbe0a45f75eb1,
75    0x36d3884e838aea68,
76    0x36ea8c1f14e2af5d,
77    0x37020a717e64a9bd,
78    0x3718851d84118908,
79    0x3730a9bdfb02d240,
80    0x3746a5bea046b42e,
81    0x375ec7f3b269efa8,
82    0x3774eafb87eab0f2,
83    0x378c6e2d05bbc000,
84    0x37a35208867c2683,
85    0x37ba425b317eeacd,
86    0x37d1d8508fa8246a,
87    0x37e840fbc08fdc8a,
88    0x38007b7112bc1ffe,
89    0x381666d0dad2961d,
90    0x382e726c3f64d0fe,
91    0x3844b0dc07cabf98,
92    0x385c1f2daf3b6a46,
93    0x38731c5957a47de2,
94    0x3889f96445648b9f,
95    0x38a1a6baeadb4fd1,
96    0x38b7fd974d372e45,
97    0x38d04da4d1452919,
98    0x38e62891f06b3450,
99    0x38fe1dd273aa8a4a,
100    0x3914775e0840bfdd,
101    0x392bd109d9d94bda,
102    0x3942e73f53fba844,
103    0x3959b138170d6bfe,
104    0x397175af0cf60ec5,
105    0x3987baee1bffa80b,
106    0x39a02057d1245ceb,
107    0x39b5eafffb34ba31,
108    0x39cdca23bae16424,
109    0x39e43e7fc88b8056,
110    0x39fb83bf23a9a9eb,
111    0x3a12b2b8dd05b318,
112    0x3a2969d47321e4cc,
113    0x3a41452b7723aed2,
114    0x3a5778fe2497184c,
115    0x3a6fe7116182e9cc,
116    0x3a85ae191a99585a,
117    0x3a9d775d87da854d,
118    0x3ab4063f8cc8bb98,
119    0x3acb374b315f87c1,
120    0x3ae27ec458c65e3c,
121    0x3af923372c67a074,
122    0x3b11152eaeb73c08,
123    0x3b2737c5645114b5,
124    0x3b3f8e6c24b5592e,
125    0x3b5571db733a9d61,
126    0x3b6d257d547e083f,
127    0x3b83ce9b9de78f85,
128    0x3b9aebabae3a41b5,
129    0x3bb24b6031b49bda,
130    0x3bc8dd5e1bb09d7e,
131    0x3be0e5b73d1ff53d,
132    0x3bf6f741de1748ec,
133    0x3c0f36bd37f42f3e,
134    0x3c2536452ee2f75c,
135    0x3c3cd480a1b74820,
136    0x3c539792499b1a24,
137    0x3c6aa0de4bf35b38,
138    0x3c82188ad6ae3303,
139    0x3c9898471fca6055,
140    0x3cb0b6c3afdde064,
141    0x3cc6b7719a59f0e0,
142    0x3cdee001eed62aa0,
143    0x3cf4fb547c775da8,
144    0x3d0c8464f7616468,
145    0x3d236121e24d3bba,
146    0x3d3a56e0c2ac7f75,
147    0x3d51e642baeb84a0,
148    0x3d6853f01d6d53ba,
149    0x3d80885298767e9a,
150    0x3d967852a7007e42,
151    0x3dae8a37a45fc32e,
152    0x3dc4c1078fe9228a,
153    0x3ddc3527e433fab1,
154    0x3df32b48bf117da2,
155    0x3e0a0db0d0ddb3ec,
156    0x3e21b48655f37267,
157    0x3e381056ff2c5772,
158    0x3e505a628c699fa1,
159    0x3e6639e3175a689d,
160    0x3e7e355bbaee85cb,
161    0x3e94875ca227ec38,
162    0x3eabe6c6fdb01612,
163    0x3ec2f6053b981d98,
164    0x3ed9c54c3b43bc8b,
165    0x3ef18354238f6764,
166    0x3f07cd79b5647c9b,
167    0x3f202cf22526545a,
168    0x3f35fc21041027ad,
169    0x3f4de16b9c24a98f,
170    0x3f644e51f113d4d6,
171    0x3f7b993fe00d5376,
172    0x3f92c155b8213cf4,
173    0x3fa97db0ccceb0af,
174    0x3fc152aaa3bf81cc,
175    0x3fd78b56362cef38,
176    0x3ff0000000000000,
177    0x4005bf0a8b145769,
178    0x401d8e64b8d4ddae,
179    0x403415e5bf6fb106,
180    0x404b4c902e273a58,
181    0x40628d389970338f,
182    0x407936dc5690c08f,
183    0x409122885aaeddaa,
184    0x40a749ea7d470c6e,
185    0x40bfa7157c470f82,
186    0x40d5829dcf950560,
187    0x40ed3c4488ee4f7f,
188    0x4103de1654d37c9a,
189    0x411b00b5916ac955,
190    0x413259ac48bf05d7,
191    0x4148f0ccafad2a87,
192    0x4160f2ebd0a80020,
193    0x417709348c0ea4f9,
194    0x418f4f22091940bd,
195    0x41a546d8f9ed26e1,
196    0x41bceb088b68e804,
197    0x41d3a6e1fd9eecfd,
198    0x41eab5adb9c43600,
199    0x420226af33b1fdc1,
200    0x4218ab7fb5475fb7,
201    0x4230c3d3920962c9,
202    0x4246c932696a6b5d,
203    0x425ef822f7f6731d,
204    0x42750bba3796379a,
205    0x428c9aae4631c056,
206    0x42a370470aec28ed,
207    0x42ba6b765d8cdf6d,
208    0x42d1f43fcc4b662c,
209    0x42e866f34a725782,
210    0x4300953e2f3a1ef7,
211    0x431689e221bc8d5b,
212    0x432ea215a1d20d76,
213    0x4344d13fbb1a001a,
214    0x435c4b334617cc67,
215    0x43733a43d282a519,
216    0x438a220d397972eb,
217    0x43a1c25c88df6862,
218    0x43b8232558201159,
219    0x43d0672a3c9eb871,
220    0x43e64b41c6d37832,
221    0x43fe4cf766fe49be,
222    0x44149767bc0483e3,
223    0x442bfc951eb8bb76,
224    0x444304d6aeca254b,
225    0x4459d97010884251,
226    0x44719103e4080b45,
227    0x4487e013cd114461,
228    0x44a03996528e074c,
229    0x44b60d4f6fdac731,
230    0x44cdf8c5af17ba3b,
231    0x44e45e3076d61699,
232    0x44fbaed16a6e0da7,
233    0x4512cffdfebde1a1,
234    0x4529919cabefcb69,
235    0x454160345c9953e3,
236    0x45579dbc9dc53c66,
237    0x45700c810d464097,
238    0x4585d009394c5c27,
239    0x459da57de8f107a8,
240    0x45b425982cf597cd,
241    0x45cb61e5ca3a5e31,
242    0x45e29bb825dfcf87,
243    0x45f94a90db0d6fe2,
244    0x46112fec759586fd,
245    0x46275c1dc469e3af,
246    0x463fbfd219c43b04,
247    0x4655936d44e1a146,
248    0x466d531d8a7ee79c,
249    0x4683ed9d24a2d51b,
250    0x469b15cfe5b6e17b,
251    0x46b268038c2c0e00,
252    0x46c9044a73545d48,
253    0x46e1002ab6218b38,
254    0x46f71b3540cbf921,
255    0x470f6799ea9c414a,
256    0x47255779b984f3eb,
257    0x473d01a210c44aa4,
258    0x4753b63da8e91210,
259    0x476aca8d6b0116b8,
260    0x478234de9e0c74e9,
261    0x4798bec7503ca477,
262    0x47b0d0eda9796b90,
263    0x47c6db0118477245,
264    0x47df1056dc7bf22d,
265    0x47f51c2cc3433801,
266    0x480cb108ffbec164,
267    0x48237f780991b584,
268    0x483a801c0ea8ac4d,
269    0x48520247cc4c46c1,
270    0x48687a0553328015,
271    0x4880a233dee4f9bb,
272    0x48969b7f55b808ba,
273    0x48aeba064644060a,
274    0x48c4e184933d9364,
275    0x48dc614fe2531841,
276    0x48f3494a9b171bf5,
277    0x490a36798b9d969b,
278    0x4921d03d8c0c04af,
279];
280
281// Lookup table for exp(m * 2^(-7)) with m = 0, ..., 127.
282// Table is generated with Sollya as follows:
283// > display = hexadecimal;
284// > for i from 0 to 127 do { D(exp(i / 128)); };
285pub(crate) static EXP_M2: [u64; 128] = [
286    0x3ff0000000000000,
287    0x3ff0202015600446,
288    0x3ff04080ab55de39,
289    0x3ff06122436410dd,
290    0x3ff08205601127ed,
291    0x3ff0a32a84e9c1f6,
292    0x3ff0c49236829e8c,
293    0x3ff0e63cfa7ab09d,
294    0x3ff1082b577d34ed,
295    0x3ff12a5dd543ccc5,
296    0x3ff14cd4fc989cd6,
297    0x3ff16f9157587069,
298    0x3ff192937074e0cd,
299    0x3ff1b5dbd3f68122,
300    0x3ff1d96b0eff0e79,
301    0x3ff1fd41afcba45e,
302    0x3ff2216045b6f5cd,
303    0x3ff245c7613b8a9b,
304    0x3ff26a7793f60164,
305    0x3ff28f7170a755fd,
306    0x3ff2b4b58b372c79,
307    0x3ff2da4478b620c7,
308    0x3ff3001ecf601af7,
309    0x3ff32645269ea829,
310    0x3ff34cb8170b5835,
311    0x3ff373783a722012,
312    0x3ff39a862bd3c106,
313    0x3ff3c1e2876834aa,
314    0x3ff3e98deaa11dcc,
315    0x3ff41188f42c3e32,
316    0x3ff439d443f5f159,
317    0x3ff462707b2bac21,
318    0x3ff48b5e3c3e8186,
319    0x3ff4b49e2ae5ac67,
320    0x3ff4de30ec211e60,
321    0x3ff50817263c13cd,
322    0x3ff5325180cfacf7,
323    0x3ff55ce0a4c58c7c,
324    0x3ff587c53c5a7af0,
325    0x3ff5b2fff3210fd9,
326    0x3ff5de9176045ff5,
327    0x3ff60a7a734ab0e8,
328    0x3ff636bb9a983258,
329    0x3ff663559cf1bc7c,
330    0x3ff690492cbf9433,
331    0x3ff6bd96fdd034a2,
332    0x3ff6eb3fc55b1e76,
333    0x3ff719443a03acb9,
334    0x3ff747a513dbef6a,
335    0x3ff776630c678bc1,
336    0x3ff7a57ede9ea23e,
337    0x3ff7d4f946f0ba8d,
338    0x3ff804d30347b546,
339    0x3ff8350cd30ac390,
340    0x3ff865a7772164c5,
341    0x3ff896a3b1f66a0e,
342    0x3ff8c802477b0010,
343    0x3ff8f9c3fd29beaf,
344    0x3ff92be99a09bf00,
345    0x3ff95e73e6b1b75e,
346    0x3ff99163ad4b1dcc,
347    0x3ff9c4b9b995509b,
348    0x3ff9f876d8e8c566,
349    0x3ffa2c9bda3a3e78,
350    0x3ffa61298e1e069c,
351    0x3ffa9620c6cb3374,
352    0x3ffacb82581eee54,
353    0x3ffb014f179fc3b8,
354    0x3ffb3787dc80f95f,
355    0x3ffb6e2d7fa5eb18,
356    0x3ffba540dba56e56,
357    0x3ffbdcc2cccd3c85,
358    0x3ffc14b431256446,
359    0x3ffc4d15e873c193,
360    0x3ffc85e8d43f7cd0,
361    0x3ffcbf2dd7d490f2,
362    0x3ffcf8e5d84758a9,
363    0x3ffd3311bc7822b4,
364    0x3ffd6db26d16cd67,
365    0x3ffda8c8d4a66969,
366    0x3ffde455df80e3c0,
367    0x3ffe205a7bdab73e,
368    0x3ffe5cd799c6a54e,
369    0x3ffe99ce2b397649,
370    0x3ffed73f240dc142,
371    0x3fff152b7a07bb76,
372    0x3fff539424d90f5e,
373    0x3fff927a1e24bb76,
374    0x3fffd1de6182f8c9,
375    0x400008e0f64294ab,
376    0x40002912df5ce72a,
377    0x400049856cd84339,
378    0x40006a39207f0a09,
379    0x40008b2e7d2035cf,
380    0x4000ac6606916501,
381    0x4000cde041b0e9ae,
382    0x4000ef9db467dcf8,
383    0x4001119ee5ac36b6,
384    0x400133e45d82e952,
385    0x4001566ea50201d7,
386    0x4001793e4652cc50,
387    0x40019c53ccb3fc6b,
388    0x4001bfafc47bda73,
389    0x4001e352bb1a74ad,
390    0x4002073d3f1bd518,
391    0x40022b6fe02a3b9c,
392    0x40024feb2f105cb8,
393    0x400274afbdbba4a6,
394    0x400299be1f3e7f1c,
395    0x4002bf16e7d2a38c,
396    0x4002e4baacdb6614,
397    0x40030aaa04e80d05,
398    0x400330e587b62b28,
399    0x4003576dce33fead,
400    0x40037e437282d4ee,
401    0x4003a5670ff972ed,
402    0x4003ccd9432682b4,
403    0x4003f49aa9d30590,
404    0x40041cabe304cb34,
405    0x4004450d8f00edd4,
406    0x40046dc04f4e5338,
407    0x400496c4c6b832da,
408    0x4004c01b9950a111,
409    0x4004e9c56c731f5d,
410    0x400513c2e6c731d7,
411    0x40053e14b042f9ca,
412    0x400568bb722dd593,
413    0x400593b7d72305bb,
414];
415
416/// Computes exp
417///
418/// Max found ULP 0.5
419#[inline]
420pub fn f_expf(x: f32) -> f32 {
421    let x_u = x.to_bits();
422    let x_abs = x_u & 0x7fff_ffffu32;
423    if x_abs >= 0x42b2_0000u32 || x_abs <= 0x3280_0000u32 {
424        let exp = ((x_u >> 23) & 0xFF) as i32;
425        // |x| < 2^-25
426        if exp <= 101i32 {
427            return 1.0 + x;
428        }
429
430        // When x < log(2^-150) or nan
431        if x_u >= 0xc2cf_f1b5u32 {
432            // exp(-Inf) = 0
433            if x.is_infinite() {
434                return 0.0;
435            }
436            // exp(nan) = nan
437            if x.is_nan() {
438                return x;
439            }
440            return 0.0;
441        }
442        // x >= 89 or nan
443        if x.is_sign_positive() && (x_u >= 0x42b2_0000) {
444            // x is +inf or nan
445            return x + f32::INFINITY;
446        }
447    }
448
449    // For -104 < x < 89, to compute exp(x), we perform the following range
450    // reduction: find hi, mid, lo such that:
451    //   x = hi + mid + lo, in which
452    //     hi is an integer,
453    //     mid * 2^7 is an integer
454    //     -2^(-8) <= lo < 2^-8.
455    // In particular,
456    //   hi + mid = round(x * 2^7) * 2^(-7).
457    // Then,
458    //   exp(x) = exp(hi + mid + lo) = exp(hi) * exp(mid) * exp(lo).
459    // We store exp(hi) and exp(mid) in the lookup tables EXP_M1 and EXP_M2
460    // respectively.  exp(lo) is computed using a degree-4 minimax polynomial
461    // generated by Sollya.
462
463    // x_hi = (hi + mid) * 2^7 = round(x * 2^7).
464    let kf = (x * 128.).round_finite();
465    // Subtract (hi + mid) from x to get lo.
466    let xd = f_fmlaf(kf, -0.0078125 /* - 1/128 */, x) as f64;
467    let mut x_hi = unsafe { kf.to_int_unchecked::<i32>() }; // it's already not indeterminate.
468    x_hi += 104 << 7;
469    // hi = x_hi >> 7
470    let exp_hi = f64::from_bits(EXP_M1[(x_hi >> 7) as usize]);
471    // mid * 2^7 = x_hi & 0x0000'007fU;
472    let exp_mid = f64::from_bits(EXP_M2[(x_hi & 0x7f) as usize]);
473    // Degree-4 minimax polynomial generated by Sollya with the following
474    // commands:
475    // d = [-2^-8, 2^-8];
476    // f_exp = expm1(x)/x;
477    // Q = fpminimax(f_exp, 3, [|D...|], [-2^-8, 2^-8]);
478    let p = f_polyeval5(
479        xd,
480        1.,
481        f64::from_bits(0x3feffffffffff777),
482        f64::from_bits(0x3fe000000000071c),
483        f64::from_bits(0x3fc555566668e5e7),
484        f64::from_bits(0x3fa55555555ef243),
485    );
486    (p * exp_hi * exp_mid) as f32
487}
488
489#[inline]
490pub(crate) fn core_expf(x: f32) -> f64 {
491    // x_hi = (hi + mid) * 2^7 = round(x * 2^7).
492    let kf = (x * 128.).round_finite();
493    // Subtract (hi + mid) from x to get lo.
494    let xd = f_fmlaf(kf, -0.0078125 /* - 1/128 */, x) as f64;
495    let mut x_hi = unsafe { kf.to_int_unchecked::<i32>() }; // it's already not indeterminate.
496    x_hi += 104 << 7;
497    // hi = x_hi >> 7
498    let exp_hi = f64::from_bits(EXP_M1[(x_hi >> 7) as usize]);
499    // mid * 2^7 = x_hi & 0x0000'007fU;
500    let exp_mid = f64::from_bits(EXP_M2[(x_hi & 0x7f) as usize]);
501    // Degree-4 minimax polynomial generated by Sollya with the following
502    // commands:
503    // d = [-2^-8, 2^-8];
504    // f_exp = expm1(x)/x;
505    // Q = fpminimax(f_exp, 3, [|D...|], [-2^-8, 2^-8]);
506    let p = f_polyeval5(
507        xd,
508        1.,
509        f64::from_bits(0x3feffffffffff777),
510        f64::from_bits(0x3fe000000000071c),
511        f64::from_bits(0x3fc555566668e5e7),
512        f64::from_bits(0x3fa55555555ef243),
513    );
514    p * exp_hi * exp_mid
515}
516
517#[inline]
518pub(crate) fn core_expdf(x: f64) -> f64 {
519    // x_hi = (hi + mid) * 2^7 = round(x * 2^7).
520    let kf = (x * 128.).round_finite();
521    // Subtract (hi + mid) from x to get lo.
522    let xd = f_fmla(kf, -0.0078125 /* - 1/128 */, x);
523    let mut x_hi = unsafe { kf.to_int_unchecked::<i32>() }; // it's already not indeterminate.
524    x_hi += 104 << 7;
525    // hi = x_hi >> 7
526    let exp_hi = f64::from_bits(EXP_M1[(x_hi >> 7) as usize]);
527    // mid * 2^7 = x_hi & 0x0000'007fU;
528    let exp_mid = f64::from_bits(EXP_M2[(x_hi & 0x7f) as usize]);
529    // Degree-4 minimax polynomial generated by Sollya with the following
530    // commands:
531    // d = [-2^-8, 2^-8];
532    // f_exp = expm1(x)/x;
533    // Q = fpminimax(f_exp, 3, [|D...|], [-2^-8, 2^-8]);
534    let p = f_polyeval5(
535        xd,
536        1.,
537        f64::from_bits(0x3feffffffffff777),
538        f64::from_bits(0x3fe000000000071c),
539        f64::from_bits(0x3fc555566668e5e7),
540        f64::from_bits(0x3fa55555555ef243),
541    );
542    p * exp_hi * exp_mid
543}
544
545#[cfg(test)]
546mod tests {
547    use super::*;
548
549    #[test]
550    fn expf_test() {
551        assert!(
552            (expf(0f32) - 1f32).abs() < 1e-6,
553            "Invalid result {}",
554            expf(0f32)
555        );
556        assert!(
557            (expf(5f32) - 148.4131591025766f32).abs() < 1e-6,
558            "Invalid result {}",
559            expf(5f32)
560        );
561    }
562
563    #[test]
564    fn f_expf_test() {
565        assert_eq!(f_expf(-103.971596), 1e-45);
566        assert!(
567            (f_expf(0f32) - 1f32).abs() < 1e-6,
568            "Invalid result {}",
569            f_expf(0f32)
570        );
571        assert!(
572            (f_expf(5f32) - 148.4131591025766f32).abs() < 1e-6,
573            "Invalid result {}",
574            f_expf(5f32)
575        );
576        assert_eq!(f_expf(f32::INFINITY), f32::INFINITY);
577        assert_eq!(f_expf(f32::NEG_INFINITY), 0.);
578        assert!(f_expf(f32::NAN).is_nan());
579    }
580}
pxfm/exponents/expf.rs

pxfm/exponents/
expf.rs
